Towing with 22"s??

I am looking to get different rims on my truck (99 f250 7.3L) considering a 20" rim with 35" tire but I like the look of 22" rim and 35" tire a little more.. I tow a 2011 Montana High Country 5th wheel (about 10-11k pounds loaded)... Any advice on if the 22" rims would make a huge difference than the 20"??